In order to ensure that parts which have been produced by means of injection molding can be removed from the tool after the injection molding process without the quality of the microstructures being impaired and in the case of a large number of microstructures without the force being excessive for removing the part from the molding tool, it is necessary to provide the microstructures with inclined surfaces which enable the part to be removed from the molding tool, which surfaces are inclined, for example, at an angle of greater than two (2) degrees, wherein this angle is measured in the cross-section between a side wall of the microstructure and a plane perpendicular to the outer surface of the part and to the cross-sectional plane.
There is a necessity to be able to produce microstructures with inclined surfaces which enable the part to removed from the molding tool and which are inclined at an angle greater, for example, than two (2) degrees particularly where the microstructures are extremely deep, for example, microstructures with a depth of 100 micrometer or a depth which is greater than 100 micrometer. This criterion is fulfilled for two-stage microstructures by the second, deeper structure and for this reason inclined surfaces which enable the part to be removed from the molding tool are essential for 2-stage microstructures.
The following processes are known which render it possible to produce parts with two-stage microstructures:    (A) Wet etching glass    (B) Dry etching silicon    (C) LIGA    (D) UV-LIGA    (E) Laser Machining    (F) Micro erosion    (G) Microcutting (drilling, machining, turning)
However, all of these known microstructuring processes are encumbered with the following disadvantages:
It is only possible to achieve a limited maximum depth of the structure using process (A). Process (B) is difficult to manage. Process (C) is extremely time-consuming and costly. The inclined surface which enables the part to be removed from the molding tool cannot be produced using process (D) or it can only be produced at great expense. The processes (E), (F), (G) have not been sufficiently developed for use in industry and in addition can only be performed in sequence.